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青少年特发性脊柱侧凸经椎弓根—肋骨复合体固定临床解剖数字化测量、个性化手术设计及有限元分析

The Measurement of Digital Clinic Anatomy, Personalized Surgical Planning and Finite Element Analysis of Pedicle Rib Unit for Fixation of the Adolescent Idiopathic Scoliosis

【作者】 付裕

【导师】 胡侦明;

【作者基本信息】 重庆医科大学 , 外科学, 2013, 博士

【摘要】 背景:青少年特发性脊柱侧凸畸形较为复杂,手术难度和风险较大,椎弓根后路固定技术可以从脊柱后路三维矫正畸形脊柱节段,其固定效果较为优良,对于该疾患的治疗起到重要的作用,但由于上、中胸段椎弓根狭窄,尤其是青少年脊椎,椎弓根尚处于发育阶段,临床手术较为困难,或者因为解剖学结构与成人差异,造成手术失误。为了解决这一问题,有学者试图在上、中胸段利用“椎弓根-肋骨复合体”进行置入,但其支持该术式的基础研究较少,手术操作过程中有许多困难。为了“椎弓根-肋骨复合体”螺钉的临床应用提供基础数据,本文做了以下研究:第一部分胸椎椎弓根-肋骨复合体的临床解剖及数字化测量目的:观察胸椎椎弓根-肋骨复合体的三维立体形态并对其临床解剖学参数进行测量。方法:选取内蒙古医科大学解剖教研室新鲜成人尸体标本6具,其中使胸椎、椎间盘、肋骨及周围软组织保留完整。对以下数据进行测量,椎弓根及椎弓根-肋骨复合体横径,椎弓根及椎弓根-肋骨复合体纵径,椎弓根螺钉固定及复合体固定螺钉走行最长距离及椎弓根及椎弓根-肋骨复合体外偏角等。测量中将尸体标本测量数据、CT影像(二维测量)与脊柱三维数字化立体重建后测量相对照比较。结果:椎弓根与肋骨的位置在胸椎的不同节段变化有一定的规律。横径为12.13-20.13mm,纵径为6.18-11.83mm,椎弓根-肋骨复合体轴线螺钉钉道最大值47.81-66.84mm,椎弓根-肋骨复合体轴线螺钉横断面外偏角为12.47-41.33°,椎弓根-肋骨复合体轴线螺钉与椎弓板的夹角为72.67-86.28°。结论:1.胸椎椎弓根-肋骨复合体的钉道长度、横径均较同节段的经椎弓根固定参数大,因此,胸椎椎弓根-肋骨复合体置钉可以使用直径更大、长度更长的螺钉,以此可以增大螺钉的把持力。2.胸椎椎弓根-肋骨复合体置钉较椎弓根螺钉要求有更大的内倾角,但其安全置钉角度范围也增大,减少手术置钉导致的螺钉穿破椎管等风险。3.经胸椎椎弓根-肋骨复合体固定螺钉直径、长度及置钉角度的选择在脊柱不同节段和个体之间差异较大,在行胸椎椎弓根-肋骨复合体置钉时要根据个体脊柱及椎骨解剖学特点制定个性化的手术方案。第二部分个性化三维数字化手术设计及临床验证目的:探讨青少年特发性脊柱侧凸数字化虚拟手术设计系统建立的方法及其在临床应用中的价值。方法:选取1例青少年特发性脊柱侧凸患者,行青少年特发性脊柱侧凸经16排螺旋CT扫描,采用Mimics10.01软件对脊柱侧凸模型进行三维重建,对三维重建模型进行数字化三维测量及置钉手术模拟,并测量固定内置物的方向、长度、直径的选择、模拟手术经过并在临床应用中使用术前模拟数据。结果:重建出青少年特发性脊柱侧凸的三维数字化虚拟可视模型,配准虚拟螺钉和椎弓根-肋骨复合体的位置,使虚拟螺钉不穿透椎弓根内侧皮质及椎体前缘,置定完整的手术方案。利用术前规划方案进行手术,手术置钉效果满意,无一例螺钉穿透椎体前缘皮质和椎管皮质。结论:验证了特发性脊柱侧凸手术术前三维数字化手术设计并制定手术方案,可以显著提高置钉手术成功率。第三部分脊柱侧凸三维有限元分析目的:建立青少年特发性脊柱侧凸的三维有限元模型,与其他模型进行验证和比较,为今后青少年特发性脊柱侧凸生物力学研究提供基础模型。方法:标本选自内蒙古医科大学第二附属医院脊柱外科就诊的青少年特发性脊柱侧凸患者一名,利用GE16排螺旋CT进行扫描,扫描层厚为1mm,利用Mimics10.01软件进行三维建模。将模型在Hypermesh进行网格划分和材料赋值。结果:1.本文建立的青少年特发性脊柱侧凸三维有限元模型共包括胸腰椎17个节段,16个椎间盘及其椎体间连接、椎弓间连接的韧带(前纵韧带、后纵韧带、黄韧带、棘间韧带及棘上韧带)。该模型采用4种单位类型,13种材料的性质,节点数为1351327,四面体单元数为1511549,壳单元数为1631320,线缆单元数为56个和42个杆单元。我们本次建立的模型外观光滑,网格划分精细,更接近真实结构。结论:1.我们研究所建模型精度较高,几何相似性好,可以在模型上进行相关生物力学研究。2.脊柱侧凸三维有限元模型可以方便地进行脊柱侧凸各种条件下的应力变化分析,为脊柱侧凸的相关生物力学理论和临床研究提供了可能。

【Abstract】 The adolescent idiopathic scoliosis is difficult to treat,It is veryimportant to use the posterior pedicle screw fixation system,although theadolescent’pedicle are narrow and complex,so the operation of it is mostdifficult than others. The pedicle rib unit fixation was good methods tosolve this questions,But the basic study to support this method wasrareless.PART ONEObjeetive:To observe the structure and measurement the clinicanatomical paremter of pedilcle rib unit.Methods:we chosed6cadavericsof the department of anatomy,Inner Mongolia Medical University,weretained the thoracic verterbra,verterbra disc and rib,we measured thefollows paremters the width,the height,the pedicle screw length and thesagittal angles of the pedicle rib unit compared with pedicle,especially forthe pedicle-rib overlap height.Results:The measurement results of theabove-mentioned parameters were as follows:PRC-W:12.13-20.13mm, PRC-H:6.18-11.83mm,PRC-L:47.81-66.84mm,PRC-TA:12.47-41.33°,PRC-SA:72.67-86.28°.Conclusions:1The width,length of pedicle rib unitare larger than the parameter of pedicle,so the strength of pedicle ribunit is larger than pedicle fixation.2The greater inward angle is largerthan pedicle fixation,so the safe angle is larger than the other,it is decreasethe danger of the operation of fixation.3There is more difference betweenpeople on pedicle rib unit paramenter,so we should desigen differentoperation plan to different patient.PART TWOThe personality3-D digital operatin design and itsappliation.Objective:To study the methods of3-D digital operatin designon adolescent idiopathic scoliosis and the application value of it.Mehtods:We chose one adolescent idiopathic scoliosis patient,and CT scaned with1mm height,and we used Mimics10.01to3D simulate model,andmeasured the parameter of the PSA,screw length and width of screw,andapplied with this parameter in operation.Results: We reconstrution the3-D model of adolescent idiopathic scoliosis,and situated the position ofscrew and pedicle rib unit,and prevent the screw to penetrate the pedicleand verterbra body,desigened the plan of operation and applied,none ofscrew was penetrate the pedicle and verterbra body.Conclusion:Thedigitalized visualization adolescent idiopathic scoliosis could increase theachievement ratio. PART THREEThe finite element analysis of correction strategies for scoliosiscorrecfion.Objeetive:To reconstructed a3-D finite element model of AISand compare tthe validity of the model,which provides a basic model forcontinue study.Methods:we chosed a patient with AIS,and used CTscanning with thickness of1millimeter.We reconstruction the3-D modelsof AIS and FEA models of AIS.Results:The finite element model containseight vertebra, seven inter-vertebral discs and related subsidiarystructure.Using4mesh types and13kinds of material parameters,themodel consists of1351327nodes,1511549tetrahedron elements,1631320shell elements,56cable elements and42rod elements.This was far more than previous similar models.The model was moreaccurate not only on structure and material properties,but also on units ofconstruction,realistic appearance and geometric similarity.Conclusions:1.The model has high quality in precision and geometric similarity,andrelative biomechanical research Can be done on it.2.Relativebiomechanical and clinical analysis Can be easily conducted on the3-Dfinite element model of scoliosis.It is possible to analyze diversity of stresson different conditions.

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